1. Field of the Invention
The invention relates to a wind power generating system with an obstruction lighting or night marking device, and with at least one rotor blade allocated to a rotor hub.
2. The Prior Art
All tall buildings constitute potential sources of danger for air traffic. To prevent accidents, tall buildings are fitted with obstruction lighting or night markings for air traffic during poor visibility, in particular for air traffic in darkness. Due to their structural height, wind power generating systems are also included among the potential sources of danger for air traffic, and must therefore be fitted with obstruction lighting or night markings.
To attain maximum safety, it is critical that the obstruction lighting or night marking device be located as close to the highest point of a building as possible, but preferably at a height where the obstruction lighting or night marking device itself constitutes the highest point of the building.
DE 200 08 289 and DE 200 15 183 U1 are wind power generating systems with an obstruction lighting or night marking device. They have electric lamps arranged in the respective hazard area.
Publication G 93 02 798.2 U1 describes an obstruction light used as a warning device for air traffic, whose light outlet element is connected to a light source a distance away by means of an optical waveguide bundle and optical aids. The light outlet element is secured to an airport, electrical tower, chimney, or telecommunications tower, and is designed as a rotationally symmetric carrier with an all-around radiation characteristic.
However, the arrangement of such obstruction lighting or night marking devices in wind power generating systems has proven to be problematic, since the highest point is located at the outer end of the turning rotor blade. The problem lies in the requirement for an overall low-maintenance power supply to the lamps situated on the turning rotor blades, and also in the attachment of the lamps or light outlet elements on the rotor blade so as to minimize the impact of the load and aerodynamics of the individual rotor blades.
There is an increased risk of lightning strikes for electrical devices located in or on the rotor blades. In addition, the supply of electrical current to lamps located on or in the rotor blades requires either the use of high-maintenance loop contacts between the rotor fixture and a rotor pivoted in the rotor fixture, or the arrangement of accumulators on the rotor. However, the latter are conceivably unsuitable for placement on or in the rotor blades given their relatively high weight. In addition, replacing spent accumulators would require shutting off the rotor every time.
An object of the invention is to create a wind power generating system whose rotor blades have an efficiently operating obstruction lighting or night marking device.
The wind power generating system provides a rotor blade having at least one optical waveguide, routed from the rotor blade hub-side end area to the rotor blade surface. A light source is provided for the optical waveguide in the rotor blade hub-side end area.
This design enables the transfer of light waves from the rotor blade hub-side end area to any region of the rotor blade. One advantage to the light source being located in the rotor blade hub-side end area is that the light source can be simultaneously used for each individual rotor blade. The light source can either be located on the rotor itself, or on non-rotating machine parts of the tower head. The advantage to the latter is that no loop contacts, rotary contacts or accumulators are required for supplying electrical power to the rotor.
It is essential that the optical waveguide is routed through the interior of the rotor blade so as not to adversely impact the aerodynamic flow conditions on the flow profile.
In a further development of the invention, the optical waveguide is designed as a fiber optical cable. Such optical cables have a bundle of flexible optical fibers, which are protected and held together by a plastic sheath. The optical cables consisting of glass fibers are used in many areas of technology, the advantage of which is that a wide range of optical cables are available on the market.
In another further development of the invention, the optical cable exhibits at least one split point, in which the optical fiber bundle is split into partial bundles toward the rotor blade surface. This design makes it possible to route the optical waveguides in various partial areas of a rotor blade. The split point is preferably located at the rotor blade tip, since this area constitutes the maximum height of the wind power generating system as the rotor turns, and so is the most important in terms of obstruction lighting.
In addition, a system for influencing the light beams is provided at each end of the partial optical fiber bundle lying in the rotor blade surface. This system aligns and orders the waves of light diffusely exiting the optical fibers into beams of light with a scattering and radiating direction that can be preset. The light beam influencing system preferably exhibits mirrors or prisms. The light beams can be influenced in nearly any manner desired by combining the mirrors and prisms.
With the framework of the invention, the light beam influencing system can be made as complex as possible, e.g., to achieve particularly effective lighting effects on the rotor blades that rotate at various speeds.
In a further development of the invention, the rotor blade exhibits a hollow body profile, which consists of at least one web running in a radial direction, and a belt enveloping the web and forming the rotor blade surface. Since particularly large wind power generating systems require obstruction lighting and night marking devices, the hollow body profile offers various ways to install or arrange the optical cable in the rotor blade. For example, the optical cable can be routed alongside the inner surfaces of the hollow body profile. It is also conceivable for the optical cable to be integrated into the web or belt. This integration can be part of the manufacturing process of a rotor blade, and protects the optical cables in the rotor blade. In addition, it is possible to design webs and belts wholly or partially out of fiberglass-reinforced plastics with light guiding properties.
The light source is preferably situated on non-rotating, fixed machine parts of the tower head, so that the hub-side end areas of the rotor blades rotate around this fixed, stationary light source. Thus, the light-absorbing surfaces are preferably arranged at the hub-end areas of the rotor blades, and connected with the optical waveguides in the rotor blades.
In a particularly advantageous configuration of the invention, the obstruction lighting or night marking device has a controller for controlling the light source. The controller offers another way of achieving useful effects on the rotating rotor blades. For example, the light source can also have a light wavelength-changing device, which controls various light colors. In another embodiment the light source can have a projector to project images, and have the images transfered to an advertising space integrated in the rotor blade surface by way of an optical fiber strand. The advertising area here consists of numerous light points, wherein at least one optical fiber is used for each light point. These advertising areas include advertising slogans or lettering in the form of brand names. One important advantage has to do with shortening the payback time for these wind power generating systems through advertising revenue.
In a further development of the invention, the rotor blades are designed so that even older wind power generating systems can be retrofitted with them. Rotor blades adjusted for these wind power generating systems provides another essential aspect of the invention.